This invention relates to a discharging protection device for battery-operated portable electric light, particularly for those types having a rechargeable battery set such as lead-acid storage battery, whereby the rechargeable battery set can be safely protected from damage by overdischarging.
At present, the main cause of damage to the rechargeable battery set can be ascribed to overdischarging. As most of the portable electric lights are not equipped with a discharging protection device for their rechargeable battery sets, whenever the electric light is left on, for instance, out of neglect, the battery set thereof will continue discharging until the voltage of the battery set drops to the lowest level, even to zero value, resulting in damage to the battery plates of, for example, a lead-acid storage battery. Therefore, replacement of the storage battery is frequently required with the known portable electric lights. While, some protection devices are, of course, available in special purpose electric lights, they are usually built with complicated circuits and thus are bulky and have more components. Consequently, as a portable electric light for general purpose usually has a limited space therein, such conventional protection devices are not only expensive but also unsuitable for practical use in them.